Recs.
Updated
Ubuntu Touch is a mobile version of the Ubuntu operating system primarily for touchscreen mobile devices such as smartphones and tablet computers.
Specs
Pros
Pro Gesture based UI
Ubuntu Touch doesn't use any physical buttons, except for power and volume buttons. To navigate you swipe from edges of the screen. Swipe buttom-to-top gives a contextual menu, swipe right-to-left switches open applications, swipe left-to-right gives quick-access to apps, swipe top-to-bottom accesses notification center.
Pro Screens hold information grouped together by topics
Ubuntu uses "scopes", functionality and information presented based on topics. Topics such as music, photos, video etc. Swiping left and right switches between these scopes. This information is pulled from various services used. So, for example, the music scope could consists of Spotify, Grooveshark and Soundcloud. The scopes can be customized.